Disclosure to Promote the Right To Information

Transcription

1 इ टरन ट म नक Disclosure to Promote the Right To Information Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public. ज न1 क अ+धक र, ज 1 क अ+धक र azdoor Kisan Shakti Sangathan The Right to Information, The Right to Live प0र 1 क छ ड न' 5 तरफ Jawaharlal Nehru Step Out From the Old to the New IS 7403 (1974): Code of practice for selection of standard worm and helical gear boxes [PGD 31: Bolts, Nuts and Fasteners Accessories]! न $ एक न' भ रत क +नम-ण Satyanarayan Gangaram Pitroda Invent a New India sing Knowledge! न एक ऐस खज न > ज कभ च0र य नहB ज सकत ह ह Bhartṛhari Nītiśatakam Knowledge is such a treasure which cannot be stolen

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4 DC ( Third-Reprint OCTOBER 1~993 ) IS: Indian Standard CODE OF PRACTICE FOR SELECTION OF STANDARD WOR AND HELICAL GEAR BOXES 1. Scope -This code has been prepared for the guidance of machinery manufacturers and users, to Tdssist in selecting correct size of worm or helical gear boxes for the application and operating conditions involved. 2. Data for Proper Selection - The following data are essential to select correct type and size of worm and helical gear boxes. 2.1 Prime over i 3) Type - Electric motor, steam engine or internal combustion engine (multi-cylinder or singlecylinder) ; b) Rated power; and c) Sneed (if variable, indicate speed range and frequency of variation). 2.2 Driven achine a) Type- Such as kiln, conveyor, etc; b) Actual power or torque necessary to drive the machine at desired speed; c) Speed; and d) Operating conditions, such as hours per day, whether continuous or intermittent, details of reversal, ambient temperature and any other special working conditions. 3. Service Factors - A gear box is rated to a specific application by the use of service factors. Service factor S is the ratio of maximum power rating of a particular size of gear box to the power required for driving the machine or equipment to which the gear box is coupled. s = aximum rated power Actual power required 3.1 Each application has its own conditions and operating requirements, and Table 1 covers the list of service factors. In this list, the first column gives the type of prime mover, and the second column the duration of service. Columns 3 to 6 cover the numerical values of the service factors, divided into four classes, corresponding respectively, with an operation with uniform, moderate shock and heavy shock loads The service factors given in Table 1 are based on the assumption that the system is free from severe critical or torsional vibrations, and that the maximum momentary or starting loads do not exceed 200 percent of the normal load (100 percent overload). 4. Application Classification - The load characteristics of various machines and-equipment in which reduction gear boxes are used, have -been classified according to their operating conditions in Table 2. This table is intended as a guide to assist in deciding the appropriate service factor for a particular duty, and should Abe used in conjunction with service factors given in Table Basic Steps for Selection 5.1 Determine Service Factor S -The appropriate service factor for the application is determined by referring to Tables 1 and Calculate Equivalent Power - Equivalent power is equal to the actual power required for driving the machine at desired speed multiplied by service factor. Equivalent power = Actual power XS 5.3 Determine Speed Ratio R - This is obtained by dividing the speed of high speed shaft, WHS by the speed of IoW speed shaft WLS. fj _ whs WLS Adopted 13 August 1974 I 0 January 1975, BIS I Gr2 BREA OF INDIAN S TANDARDS ANAK BHAVAN. 9 BAHADR SHAH ZAFAR ARG NEW DELHI

5 IS : Select Size from Rating Table - The rated power for the size of unit selected should be equal to, or greater than the calculated equivalent.power for the given speed ratio of the gear box selected. 5.5 Check for omentary or Peak Load- The gear box selected can take momentary roads of twice the rated power. However, in case the peak power requirements of the-driven machine exceeds by more than 100 percent the rated power, the size selected should have rated power equal to or greater than half of the peak power. omentary load means a load which acts for a period of not more than 15 seconds. 5.6 Check Brake Torque - When a motor or engine is equipped with brake, whose torque rating exceeds that of the motor or engine, the torque rating of gear box selected should exceed brake toraue, all other things being equal. 5.7 Check Overhung Load - If a sprocket, pulley or spur pinion is mounted on the output shaft, over- ~hung load is imposed on the shaft. The equivalent overhung load in kg is calculated as under: p _Ax975000xK - NxR where P= A= K= N= R= The load factors equivalent overhung load in kg ; actual power carried by the shaft in kw; load factor; shaft speed in rpm; and pitch radius of sprocket, pulley or spur pinion in mm. are as under: Overhung ember K Sprocket 1.00 Spur pinion 1.25 V-belt sheave 1.50 <Iat belt pulley The calculated overhung loads should be less than the maximum permissible overhung loads on gear boxes. TABLE 1 SERVICE FACTORS (Clauses 3.1.l, 4 and!.i ) Prime over Duration of Service Hours/Day Service Factors I Nature of Load on Gear nit from Driven*achine niform oderate Shock Heavy Shock Worm Heavy Shock, Helical and Spur (1) (2) (3) (4) (5) (6) El;;yrd;nzotor or steam : o l : oo ~ ulti-cylinder internal combustion engine z 1.o :::5 ::; ::;z :t ::: Single-cylinder internal z 1.l combustion engine :t

6 TABLE 2 LQAD CHARACTERISTICS VALES FOR DIFFERENT APPLICATIONS (Clauses 4 and 5.1) - J = niform Load ti = oderate Shock Load Driven achine H=Heavy Shock Load HI= High Inertia Load. anufacturer, t to be consu!ted. Type of Load Driven achine Type of Load - Igitators: Pure liquids Liquids and solids Liquids -variable 3lowers: &;rifugal Vane density 3rewing and distilling: Bottling machinery Brew kettles - continuous duty Cookers-continuous duty ash tubes-continuous duty Scale hopper-frequent starts Tan filling machines Cane knives Tar dumpers Tar pullers Tlarifiers Tlassifiers Clay working machinery: Brick press Briquette machine Clay working machinery Pug mill Zompressors: Ca;terifugal Reciprocating Single-cylinder multi-cylinder Conveyors-uniformly loaded or fed: Apron %:mbly Bucket Chain Flight Oven Screw Conveyors-heavy Apron %emb y Bucket Chain Flight Live roll Oven Reciprocating Screw Shaker Cranes: ain hoists Bridge travel Trolley travel Crusher: Ore Stone Sugar Dredges: Cable reels Conveyors Cutter head drives duty not uniformly fed:! : H! 1 Jig drives anoeuvering Pumps Screen drive Stackers tility winches winches Dry dock cranes: ain hoist Auxiliary hoist Boom, luffing Rotating swing or slew Tracking, drive wheels Elevators: Bucket-uniform load Bucket-heavy load Centrifugal discharge Bucket continuous Escalators Freight Gravity discharge an lifts Passenger lifts Fans: Centrifugal Induced draft Large-mine, etc Large-industrial Light-smaller diameter Feeders: zon Disc Reciprocating Screw Food industry: Beef slicer Cereal cooker Dough mixer eat grinders Generators- hot weld;ng Hammer mills Hoists: Heavy duty edium duty Skip laundry washers reversing Laundry tumblers Line shafts: Driving processing equipment Light Other line shafts Lumber industry: Barkers-hydraulic-mechanical Burner conveyor Chain saw and drag saw Chain transfer Craneway transfer De-barking drum Edger feed Gang f ed Green I hain Live rolls Log deck Log haul-incline Log haul-well type Log turning device ( Continued) 3

7 IS: TABLE 2 LOAD C~HARACTERISTICS VALES FOR DIFFERENT APPLICATIONS-Contd Driven achine Type of Load Driven achine Type of Load ain log conveyor Off bearing rolls Planer feed chains Planer floor chains Planer tilting hoist Re-saw merry-go-round conveyor Roll cases Slab conveyor Small waste conveyor-belt Small waste conveyor-chain Sorting table Tipple hoist conveyor Tipple hoist drive Transfer conveyors Transfer rolls Tray drive Trimmer feed Waste conveyor achine tools: Bending roll Punch press-gear driven Notching press-belt driven Plate planers Tapping machine mother machine tools and main drive Auxiliary drives etal mills; Draw bench carriage and main drive Pinch, dryer and slitters Table conveyors non-reversing group drives Wire drawing and flattening machine Wire winding machine Reversing i&-rotary type: Cement kilns Dryers and coolers FtGl;;other than cement Rod : Plain Wedge bar Log haul Presses Pulp machine reel Stock chest Suction role Washers and thickeners Winders Printing presses Pullers: Barge haul Pumps: F Centrifugal Proportioning Reciprocating : Single acting, 3 or more cylinders Double acting, 2 or more cylinders Single acting, 1 or 2 cylinders Rotary Gear type Lobe, vane grubber and plastics industries: Crackers Laboratory equipment ixing mills Refiners Rubber calenders Rubber mill-2 on line Rubber mill-3 on line Sheeter Tubers and strainers Warming mills Sand muller Sewage disposal equipment: Bar screens Chemical feeders Collectors Dewatenng screws Scum breakers Slow or rapid mixers Thickeners Vacuum filters :: 1 HI Tumbling barrels ixers: Concrete mixers-continuous Intermittent Constant density Variable density Oil industry: Chillers Paraffin filter press Rotary kilns Paper mills: Agitators (mixers) Barker-auxiliaries-hydraulic Barker-mechanical Barking drum Beater and pulper Bleacher Calendars Calendars, super Converting machine, except platers fzzz;;yors Cutters-platers Cylinders Dryers Felt stretcher Felt whipper Jordans cutters- Screens: Air washing Rotary-stone or gravel Travelling water~intake Slab pushers Stockers Sugar industry: Cane knives Crushers ills Textile industry: Batchers Calenders Cards Dry cans Dryers Fybei~ machinery angles ;$rrs Slashers Soaps Spinners Tenter frames Washers Winders Windlass Ii 4 Reprography nit, BIS, New Delhi, India